Title

Author

Document Type

Thesis - University Access Only

Award Date

1989

Degree Name

Master of Science (MS)

Department

Dairy Science

First Advisor

Robert J. Baer

Abstract

In the past decade, the cheese industry in the United States has grown rapidly with cheese sales increasing by 39% (58). In 1977, 23.5% of the United States milk supply was utilized by the cheese industry, that has grown to 30.0% in 1987 (58). Cheddar cheese production increased from 1 billion kg in 1979, to 1.27 billion kg in 1986. During this same time period, Italian cheese production increased from .40 to .72 billion kg. Other types of cheeses, for example cream cheese, experienced production increases of more than 30%; Muenster production increased 25% (58). However, Cheddar cheese still represents the largest single type of cheese produced in the United States (54). Since growth appears to be slowing, Cheddar cheese makers must increase yield (5, 81) and efficiency (5) in order to increase or maintain profit. One concept that allows cheesemakers to increase efficiency and yield is concentrating milk before cheese manufacture. Concentrating milk allows more efficient use of plant equipment and labor, and eases the problem of whey disposal. Efficiency is improved by allowing more cheese to be manufactured without increasing the number of vats or labor. In addition, concentration has been shown to increase yield (5, 9, ·22, 32, 37, 39, 52). The five methods of concentrating milk are ultrafiltration (UF), reverse osmosis (RO), vacuum concentration, reconstitution, and supplementation. Ultrafiltration removes water, lactose, and some minerals from milk, while vacuum concentration and RO remove only water. Ultrafiltration and RO are accomplished by passing milk across a semi-permable membrane under pressure. Molecules of small size, such as water, lactose, and some minerals are forced out while protein and fat, which are relatively large molecules, are retained by the UF membrane. Vacuum concentration uses heat and vacuum to remove water from milk. Reconstituted milk is produced by addition of water to dried milk powder where supplementation is addition of dried milk powder or concentrated milk to whole or skim milk to increase total solids content. Homogenization is the process of breaking the fat globules into smaller globules, usually less than 1 um in size (89). Homogenization increases fat globule surface area 4 to 10 times. Mabbit and Cheeseman (47) showed that additional proteins are absorbed into the milk fat globule membrane during homogenization. The benefits of using homogenized milk for cheese manufacture are lower fat losses in whey, higher cheese yield, reduced fat leakage, and less shrinkage during ripening and storage (66). The purpose of this research was to determine the effect of vacuum concentration of milk to 21.5% total solids on Cheddar cheese manufacture. The partial homogenization effect of condensing milk on yield and quality of Cheddar cheese was evaluated.